The central goal of our studies is to define the mechanisms that control the age-associated changes of the T cell repertoire. A dramatic example of the B cell changes that occur frequently with age is the occurrence of so-called Benign B cell Monoconal Gammapathy (BBMG). Our prelimary results suggest that we have found what could be the T cell equivalent to BBMG. The overall goal of this proposal is to investigate the nature and biological significance of CD8+ CD28-clonal expansions which occur in elderly humans.